(1) FIELD OF THE INVENTION
The present invention relates to a simple and highly advantageous process of continuously producing alkali metal superoxides and more particularly of potassium superoxide as well as to an apparatus which is especially suitable for carrying out said process.
(2) THE PRIOR ART
Potassium superoxide of the Formula KO.sub.2 is extensively used as oxygen-supplying agent, for instance, for the automatic regeneration of air to be inhaled.
Said compound is produced in accordance with known processes by reacting hydrogen peroxide with potassium hydroxide. Technically used processes of this type comprise a first reaction step in which a hydrogen peroxide solution is reacted with an aqueous potassium hydroxide solution under carefully controlled reaction temperature conditions.
Thus, for instance, in accordance with German application No. 23 13 116 which has been laid open for public inspection, there are added the two reactants in properly adjusted molecular proportions to a previously prepared mixture of the reactants whereby the reaction solution is kept at a reaction temperature below 10.degree. C. Subsequently the reaction solution which contains as initial reaction product an addition compound composed of potassium peroxide and hydrogen peroxide (potassium peroxide-di-hydrogen peroxidate) is subjected in a second reaction step to rapid dehydration in a small spot-like zone in order to produce potassium superoxide.
According to Japan Kokai No. 71 70,896 (Chem. Abstr. 81, 172 403x) there is produced a mixture with a hydrogen peroxide: potassium hydroxide ratio of 1.75 from a 50% aqueous potassium hydroxide solution and a 60% aqueous hydrogen peroxide solution at a temperature between 15.degree. C. and 35.degree. C. Said mixture is subsequently subjected to spray drying to yield potassium superoxide.
Both processes have substantial disadvantages. Thus considerable expenditures are involved on carrying out the first mentioned process. Both processes require first the preparation of an aqueous reaction mixture in which losses due to decomposition must be kept within tolerable limits by careful temperature control. Due to the strongly exothermic reaction taking place it is necessary to provide cooling devices of correspondingly large dimensions. This has a disadvantageous effect upon the economy of the two processes.